1. Field of the Invention
This invention relates to a stackable low depth tray for storing and transporting beverage containers, such as bottles.
2. Background Art
Bottles, particularly for soft drinks and other beverages, are often stored and transported in trays. The term “tray” as used herein includes trays, crates, cases, and similar containers having a floor and a peripheral side wall structure. As compared with other materials, plastic trays provide advantages such as strength, durability, and reusability. In order to minimize the storage space of trays, reduce their cost and weight, and promote display of the bottles contained therein, many trays are constructed to have shallow side and end walls. Such trays are generally referred to as “low depth” trays in which the side and end walls are lower than the height of the stored bottles, and in which the bottles support the weight of additional trays stacked on top.
In general, bottles go through a bottling facility and to the bottler's warehouse in the following order: the bottles are filled, sealed, loaded into trays, and then layers of trays are placed on pallets. Trays in successive layers are stacked or cross-stacked on top of each other, with the bottles bearing most of the load of above-stacked trays. The stacks of trays must be particularly stable in order to remain standing during the jostling inherent when the pallets are moved into and out of the warehouse.
Plastic bottles are widely used as containers for retailing soft drinks and other beverages. One type of plastic, polyethylene terephthalate (PET), has become particularly popular because of its transparency, light weight, and low cost. In addition to being flexible, the walls of PET bottles are strong in tension and thus can safely contain the pressure of a carbonated beverage. Moreover, conventional PET bottles can bear relatively high compressive loads, provided that the load is directed substantially along an axially symmetric axis of the bottle. A single PET bottle can support the weight of many bottles of the same size filled with beverage if the bottle is standing upright on a flat, horizontal surface and the weight of the other bottles is applied to the closure of the single bottle and is directed substantially vertically along its symmetric axis. However, if a compressive load is applied to a conventional PET beverage bottle along a direction other than the symmetry axis of the bottle, the bottle may buckle, particularly for large capacity bottles such as the two-liter bottle widely used for marketing soft drinks.
Bottles can also tilt away from vertical alignment upon stacking if conventional partitioned trays having low side walls are used to contain the bottles. Tilted bottles in the lower trays of a stack can buckle, causing the stack to fall. Even absent buckling, the tendency of bottles to tilt in conventional low-sided trays causes instability and places an undesirably low limit on the number of tiers that can be included in a stack.
With the aforementioned issues regarding bottle stability and storage and handling processes in mind, there are several features which are desirable for the design of low depth bottle trays. Generally, low depth trays should have a wall structure that provides sufficient support for the bottles stored therein while also allowing the bottles to be visible for merchandising purposes. In addition, trays should be designed with structural features which enhance their stability when stacked and cross-stacked. Still further, the trays should have sufficient strength and rigidity to withstand shipping and handling. Lastly, the trays should be lightweight, easy to manipulate and carry, and efficient to mold.
Current low depth trays are typically designed with a trade-off between strength and weight, wherein material is often removed to decrease weight, thus reducing structural integrity or bottle stability. Also, many low depth trays are inefficient to mold, typically due to the design of bottle support members which extend upwardly from and within the low side walls. Long mold times render trays susceptible to uneven cooling, which can cause warping and dimensional inaccuracies as well as possibly decreasing the life of the tray.